872417 - B2G Emulator: support FMRadio emulation

Status: RESOLVED WONTFIX

(Firefox OS Graveyard :: Emulator, defect)

Description

[Vicamo Yang [:vicamo][:vyang]]

Per bug 862672 comment 52, we might need an emulated FM chip for further testing.

The FM hardware we're using for Unagi is WCN2243, code named Bahama[1], supported by Qualcomm Tavarua FM core driver[2].

The major mission here should be implement minimum necessary drivers, host emulation for Gecko FMRadio component while providing console commands that enables further automation tests as well.  Known requirements/limits[3] are:

  1) handset switch in /devices/virtual/switch/h2w
  2) V4L2 device in /dev/radio0. Supported ioctls are VIDIOC_QUERYCAP, 
    2.1) VIDIOC_QUERYCAP (get capabilities):
      2.1.1) V4L2_CAP_RADIO,
      2.1.2) V4L2_CAP_TUNER
    2.2) VIDIOC_S_CTRL (control set):
      2.2.1) V4L2_CID_PRIVATE_TAVARUA_STATE (FM_RECV & FM_OFF),
      2.2.2) V4L2_CID_PRIVATE_TAVARUA_EMPHASIS,
      2.2.3) V4L2_CID_PRIVATE_TAVARUA_RDS_STD (always 0),
      2.2.4) V4L2_CID_PRIVATE_TAVARUA_SPACING,
      2.2.5) V4L2_CID_PRIVATE_TAVARUA_REGION,
      2.2.6) V4L2_CID_PRIVATE_TAVARUA_SET_AUDIO_PATH,
    2.3) VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY (get frequency)
    2.4) VIDIOC_S_TUNER, VIDIOC_G_TUNER (tuner attributes):
      2.4.1) rangelow,
      2.4.2) rangehigh
    2.5) VIDIOC_DQBUF (exchange a buffer with the driver)
    2.6) VIDIOC_S_HW_FREQ_SEEK (perform a hardware frequency seek)
  3) Android properties
    3.1) "hw.fm.version": WO,
    3.2) "hw.fm.mode": WO, "normal" or "config_dac"
    3.3) "hw.fm.init": RO, 
    3.4) "ro.moz.fm.noAnalog": RO
    3.5) "hw.fm.isAnalog": WO
  4) Android service:
    4.1) "fm_dl": oneshot service, write pre-configured parameters to device.

[1]: https://www.codeaurora.org/gitweb/quic/le/?p=kernel/msm.git;a=commitdiff;h=31b2fd9ccd06f593ddd987dd13b29e42cebcf93a
[2]: https://www.codeaurora.org/gitweb/quic/le/?p=kernel/msm.git;a=blob;f=drivers/media/radio/radio-tavarua.c;h=afc36408fd7b476993c811a40211b809b2c29cd4;hb=refs/heads/ics_chocolate_rb4.2
[3]: https://mxr.mozilla.org/mozilla-central/source/hal/gonk/GonkFMRadio.cpp

Comment 1

[Pin Zhang [:pzhang] (inactive)]

Looking forward to it!

Comment 2

[Vicamo Yang [:vicamo][:vyang]]

Mostly V4L2 stuff are necessary and don't seem to me some serious problems.  We can also fill user buffer with some random data.

For Android properties and fm_dl service, currently we don't break the whole initialization process for their absence.  That 4-second wait loop also acts as a hardware delay that we need to reproduce bug 862672.

Looks doable for me.

Comment 3

[Vicamo Yang [:vicamo][:vyang]]

But I'd like to add: hard-code some hardware initialization code in Gecko is really unwise.  We should split them into some HAL module that implements a predefined common interface as possible.

Comment 4

[Vicamo Yang [:vicamo][:vyang]]

WIP branch: https://github.com/vicamo/b2g_kernel_goldfish/tree/bugzilla/872417/goldfish-fm

Comment 5

[StevenLee[:slee]]

In the current implementation of FM Radio, we may need these functions. I know there are some discussions about RDS support but this future is not enabled on unagi.
* EnableFMRadio: Initialize FM chip (async)
* DisableFMRadio: Release FM resource (async)
* FMRadioSeek: Seek FM frequency with up/down direction (async)
* GetFMRadioFrequency: Get current frequency (sync)
* SetFMRadioFrequency: Set specific frequency (sync)
* GetFMRadioSignalStrength: Get signal strength (sync)

Comment 6

[Pin Zhang [:pzhang] (inactive)]

(In reply to StevenLee from comment #5)
> In the current implementation of FM Radio, we may need these functions. I
> know there are some discussions about RDS support but this future is not
> enabled on unagi.
> * EnableFMRadio: Initialize FM chip (async)
> * DisableFMRadio: Release FM resource (async)
> * FMRadioSeek: Seek FM frequency with up/down direction (async)
> * GetFMRadioFrequency: Get current frequency (sync)
> * SetFMRadioFrequency: Set specific frequency (sync)
> * GetFMRadioSignalStrength: Get signal strength (sync)

How about IsFMRadioOn and GetFMRadioSettings?

Comment 7

[Vicamo Yang [:vicamo][:vyang]]

(In reply to Vicamo Yang [:vicamo][:vyang] from comment #2)
> Mostly V4L2 stuff are necessary and don't seem to me some serious problems. 
> We can also fill user buffer with some random data.

Just find I'm wrong.  VIDIOC_DQBUF is not for audio data, but for retrieving state transition status.  So we're surely has to fill correct data according to current operation state.

Comment 8

[Vicamo Yang [:vicamo][:vyang]]

(In reply to StevenLee from comment #5)
> In the current implementation of FM Radio, we may need these functions. I
> know there are some discussions about RDS support but this future is not
> enabled on unagi.

There might be some misunderstandings.  Emulation here won't alter a line of code in Gecko.

Comment 9

[Vicamo Yang [:vicamo][:vyang]]

From bug 885370, we may add a GonkFM_Goldfish.cpp to completely ignore behaviours of Qualcomm WCN2243 and define our own virtual FM hardware.

Comment 10

[Vicamo Yang [:vicamo][:vyang]]

WIP: https://github.com/mozilla-b2g/kernel_goldfish/pull/7

Comment 11

[Michael Wu [:mwu]]

FYI, Tavarua support should be the only driver specific thing. It was a hack to make the 1.0 release. There is a full V4L2 standard mode in the FM backend which only uses standard V4L2 calls to setup the FM radio. I recommend testing that mode instead of Tavarua/MSM mode. I wrote a FM radio driver which works with it that may be helpful as a reference - https://bugzilla.mozilla.org/attachment.cgi?id=8334519&action=diff .

Comment 12

[BMO Automation]

Firefox OS is not being worked on